Name:	eqr_ConsolidatedProjectUnderDevelopmentCommitmentFund
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of consolidated projects in various stages of development.

No definition available.

Name:	eqr_NumberOfConsolidatedProjectsInVariousStagesOfDevelopment
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of open development projects. May include projects that are held for and/or under development, completed and not stabilized or completed and stabilized. These projects are consolidated.

No definition available.

Name:	eqr_NumberOfProjectsInVariousStagesOfDevelopment
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of real estate technology investments.

No definition available.

Name:	eqr_NumberOfRealEstateTechnologyInvestments
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of unconsolidated projects in various stages of development.

No definition available.

Name:	eqr_NumberOfUnconsolidatedProjectsInVariousStagesOfDevelopment
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Total number of units that are associated with open development projects. May include projects that are held for and/or under development, completed and not stabilized or completed and stabilized. These units are consolidated.

No definition available.

Name:	eqr_NumberOfUnitsInVariousStagesOfDevelopment
Namespace Prefix:	eqr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Project under development commitment fund.

No definition available.

Name:	eqr_ProjectUnderDevelopmentCommitmentFund
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Real estate technology investments commitment fund.

No definition available.

Name:	eqr_RealEstateTechnologyInvestmentsCommitmentFund
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Unconsolidated project under development commitment fund.

No definition available.

Name:	eqr_UnconsolidatedProjectUnderDevelopmentCommitmentFund
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_RealEstatePropertiesAxis=eqr_ProjectsUnderDevelopmentConsolidatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RealEstatePropertiesAxis=eqr_ProjectsUnderDevelopmentUnconsolidatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RealEstatePropertiesAxis=eqr_ProjectsUnderDevelopmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: